qt: move pubkey_to_q_icon in qt.util

diff --git a/electrum/gui/qt/confirm_tx_dialog.py b/electrum/gui/qt/confirm_tx_dialog.py
index 2722417..3935db7 100644
--- a/electrum/gui/qt/confirm_tx_dialog.py
+++ b/electrum/gui/qt/confirm_tx_dialog.py
@@ -47,7 +47,8 @@ from electrum.submarine_swaps import NostrTransport, HttpTransport
 from .seed_dialog import seed_warning_msg
 
 from .util import (WindowModalDialog, ColorScheme, HelpLabel, Buttons, CancelButton, WWLabel,
-                   read_QIcon, debug_widget_layouts, qt_event_listener, QtEventListener, IconLabel)
+                   read_QIcon, debug_widget_layouts, qt_event_listener, QtEventListener, IconLabel,
+                   pubkey_to_q_icon)
 from .transaction_dialog import TxSizeLabel, TxFiatLabel, TxInOutWidget
 from .fee_slider import FeeSlider, FeeComboBox
 from .amountedit import FeerateEdit, BTCAmountEdit
@@ -885,7 +886,7 @@ class TxEditor(WindowModalDialog, QtEventListener, Logger):
             self.server_button.setEnabled(True)
             if self.config.SWAPSERVER_NPUB:
                 pubkey = from_nip19(self.config.SWAPSERVER_NPUB)['object'].hex()
-                self.server_button.setIcon(SwapServerDialog.pubkey_to_q_icon(pubkey))
+                self.server_button.setIcon(pubkey_to_q_icon(pubkey))
             self.server_button.setText(
                 f' {len(self.swap_transport.get_recent_offers())} ' +
                 (_('providers') if len(self.swap_transport.get_recent_offers()) != 1 else _('provider'))
diff --git a/electrum/gui/qt/swap_dialog.py b/electrum/gui/qt/swap_dialog.py
index 859da78..2a612e9 100644
--- a/electrum/gui/qt/swap_dialog.py
+++ b/electrum/gui/qt/swap_dialog.py
@@ -13,12 +13,13 @@ from electrum.util import NotEnoughFunds, NoDynamicFeeEstimates, UserCancelled
 from electrum.bitcoin import DummyAddress
 from electrum.transaction import PartialTxOutput, PartialTransaction
 from electrum.fee_policy import FeePolicy
-from electrum.submarine_swaps import NostrTransport, pubkey_to_rgb_color
+from electrum.submarine_swaps import NostrTransport
 
 from electrum.gui import messages
 from . import util
 from .util import (WindowModalDialog, Buttons, OkButton, CancelButton,
-                   EnterButton, ColorScheme, WWLabel, read_QIcon, IconLabel, char_width_in_lineedit)
+                   EnterButton, ColorScheme, WWLabel, read_QIcon, IconLabel, char_width_in_lineedit,
+                   pubkey_to_q_icon)
 from .util import qt_event_listener, QtEventListener
 from .amountedit import BTCAmountEdit
 from .fee_slider import FeeSlider, FeeComboBox
@@ -301,7 +302,7 @@ class SwapDialog(WindowModalDialog, QtEventListener):
         self.needs_tx_update = True
         # update icon
         pubkey = from_nip19(self.config.SWAPSERVER_NPUB)['object'].hex() if self.config.SWAPSERVER_NPUB else ''
-        self.server_button.setIcon(SwapServerDialog.pubkey_to_q_icon(pubkey))
+        self.server_button.setIcon(pubkey_to_q_icon(pubkey))
 
     def get_client_swap_limits_sat(self) -> Tuple[int, int]:
         """Returns the (min, max) client swap limits in sat."""
@@ -531,13 +532,7 @@ class SwapServerDialog(WindowModalDialog, QtEventListener):
             labels[self.Columns.LAST_SEEN] = age(x.timestamp)
             item = QTreeWidgetItem(labels)
             item.setData(self.Columns.PUBKEY, ROLE_NPUB, x.server_npub)
-            item.setIcon(self.Columns.PUBKEY, self.pubkey_to_q_icon(x.server_pubkey))
+            item.setIcon(self.Columns.PUBKEY, pubkey_to_q_icon(x.server_pubkey))
             items.append(item)
         self.servers_list.insertTopLevelItems(0, items)
 
-    @staticmethod
-    def pubkey_to_q_icon(server_pubkey: str) -> QIcon:
-        color = QColor(*pubkey_to_rgb_color(server_pubkey))
-        color_pixmap = QPixmap(100, 100)
-        color_pixmap.fill(color)
-        return QIcon(color_pixmap)
diff --git a/electrum/gui/qt/util.py b/electrum/gui/qt/util.py
index aad0db5..3f11a60 100644
--- a/electrum/gui/qt/util.py
+++ b/electrum/gui/qt/util.py
@@ -26,6 +26,7 @@ from electrum.util import (FileImportFailed, FileExportFailed, resource_path, Ev
 from electrum.invoices import (PR_UNPAID, PR_PAID, PR_EXPIRED, PR_INFLIGHT, PR_UNKNOWN, PR_FAILED, PR_ROUTING,
                                PR_UNCONFIRMED, PR_BROADCASTING, PR_BROADCAST)
 from electrum.qrreader import MissingQrDetectionLib, QrCodeResult
+from electrum.submarine_swaps import pubkey_to_rgb_color
 
 from electrum.gui.common_qt.util import TaskThread
 
@@ -726,6 +727,13 @@ def get_icon_camera() -> QIcon:
     return read_QIcon(name)
 
 
+def pubkey_to_q_icon(server_pubkey: str) -> QIcon:
+    color = QColor(*pubkey_to_rgb_color(server_pubkey))
+    color_pixmap = QPixmap(100, 100)
+    color_pixmap.fill(color)
+    return QIcon(color_pixmap)
+
+
 def add_input_actions_to_context_menu(gih: 'GenericInputHandler', m: QMenu) -> None:
     if gih.on_qr_from_camera_input_btn:
         m.addAction(get_icon_camera(), _("Read QR code with camera"), gih.on_qr_from_camera_input_btn)